Automatic bending machine for manufacturing of steel rule cutting dies

ABSTRACT

A setup method for preventing a “two-leaf cutting” by only operating a machine without using fingers in cutting an end of a strip blade material having an enclosed rectangular geometry. The steps include: the strip blade material being once advanced to a position, where “two-leaf cutting” will not occur; then a cutting tool being lowered; a cutting tool tip of a cutting tool component being lowered to a level of the same as or under that of a top edge of the strip blade material; then the strip blade material being retracted; and finally, the strip blade material being retracted by the same amount as that of the advance from the desired position.

This application is a divisional of Ser. No. 11/201,133, filed Aug. 11,2005, now allowed, which claims the benefits of Japanese PatentApplication 2005-184059, filed May 27, 2005, the contents of which areincorporated herein in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an automatic bending machine formanufacturing of steel rule cutting dies which are used to form aprescribed cut or rule on a cardboard, a corrugated board, or the like,in manufacturing a paper container, a corrugated board container, or thelike, and particularly to an automatic bending machine for carrying outbending, cutting, and the like, of a strip blade material constituting asteel rule cutting die.

Since, in 1988, Suchiro Mizukawa published the world-first automaticbending machine for manufacturing of steel rule cutting dies (providedwith a trade name of BBS-101), the automatic bending machine of thistype has been greatly improved. For example, in the following patentdocuments 1 and 2, an automatic bending machine for carrying outbending, cutting, and the like, of a strip blade material constituting asteel rule cutting die is disclosed, respectively.

Patent documents 1: U.S. Pat. No. 6,629,442

Patent documents 2: U.S. Pat. No. 5,787,750

Patent documents 3: Japanese Patent Publication No. JP/11-347828A/1999

Patent documents 4: Japanese Patent Publication No. JP/2001-314932A

The bending tool of U.S. Pat. No. 6,158,264 by Suchiro Mizukawa was abending tool which is concentrically operated, as shown in FIG. 9-A,thus the maximum bending angle was 90 degrees. The bending tool canactually be turned by an angle of over 90 degrees, however, because aspringback occurs with the strip blade material 5 bent, the maximumbending angle was limited to 90 degrees. This mechanism is simple,providing a sturdy tooling, thus being high in reliability. In addition,the simple construction requires no extra motor or cylinder. Thisinvention includes no mechanism for cutting both ends of the strip bladematerial.

Conventionally, bending tools which have a bending capacity of more than90 degrees have been available; for example, those as disclosed in U.S.Pat. No. 4,627,255 and U.S. Pat. No. 5,787,750. With these tools, twobending members are alternately moved in a vertical direction on bothsides of the strip blade material 5. There is the possibility that thetwo bending members may be struck against the bottom of the workpiece,resulting in jamming, when they are moved upward. In addition, thenumber of bending members provided is two rather than one, which takesan increased working time. Because the bending members are onlyinserted, there was the need for introducing a synchronizing mechanismin order to eliminate the possibility of damaging them. In addition, anextra mechanism for vertically moving the bending members is required.(Referring to the construction as shown in FIGS. 9-B)

With the cutting mechanism as disclosed in U.S. Pat. No. 5,787,750, bothends of the workpiece are straight-cut or miter-cut prior to the bendingby the bending mechanism. This method will not provide accuracy of thelength. The invention of U.S. Pat. No. 6,629,442 uses the cuttingmechanism as disclosed in U.S. Pat. No. 6,324,953. However, the type ofcutting is limited to straight cutting. FIG. 10-A illustrates thecutting mechanism as disclosed in U.S. Pat. No. 6,227,026, which usestwo scissors-like movable tools 6 to cut only the top portion of theblade material at both ends. The body portion thereof is separately cutby means of a bridge cutting tool. In other words, a two-stage cuttingis carried out.

FIG. 10-B and FIG. 10-C illustrate the cutting mechanism as disclosed inU.S. Pat. No. 6,324,953, which eliminates the need for two-stagecutting, but cutting is performed on both sides of the stationary blade61, which requires a separate cylinder for displacement between sides ofthe blade 61.

When any of these cutting mechanisms is used to cut a blade materialhaving an enclosed rectangular geometry as shown in FIG. 13-A in themanner as illustrated in FIG. 13-B, “two-leaf cutting” is caused,resulting in the workpiece as a product being damaged.

The bending mechanism as disclosed in U.S. Pat. No. 6,629,442 provides acomplex construction in which two bending tools are incorporated in adouble gear, one of them being turned in a clockwise direction by thegear which is vertically moved by a separate motor, while the otherbeing turned counterclockwise.

SUMMARY OF THE INVENTION

The most important purpose of the present invention is to provide abending tool which is sturdy and having precision, having a capabilityof bending the workpiece to an angle as deep as over 90 degrees, withoutthe need for using any extra device, such as motor, cylinder, and thelike.

The present invention provides an automatic bending machine forautomatically bending a strip blade material, wherein the automaticbending machine intermittently feeds a strip blade material 5 through anozzle 3 until the strip blade material 5 is jutted out from a nozzlegate 31 at the end of the nozzle 3, and causes a CW-direction bendingtool 4 or a CCW-direction bending tool 40 to be turned in a clockwisedirection or a counterclockwise direction, respectively, to strike thestrip blade material 5 for bending it; the CW-direction bending tool 4and the CCW-direction bending tool 40 being provided with a bending toolsupport 42 extending at right angles thereto and having a concentrichole 41, at the top and bottom of the CW-direction bending tool 4 andthe CCW-direction bending tool 40, respectively; the CW-directionbending tool 4 and the CCW-direction bending tool 40 being superposedone upon the other; a nozzle column 32 or a reinforcing rod 1021provided on the top of the nozzle 3, penetrating through the concentrichole 41; and a protrusion 22 being provided on the top of a lower beltwheel 21 turned under the control of a computer, being in contact withthe bending tool support 42. More specifically, when the lower beltwheel 21 is turned, the protrusion 22 thereon is also turned. And, whenthe protrusion 22 is turned clockwise or counterclockwise, it forces theCW-direction bending tool 4 or the CCW-direction bending tool 40 tostrike the strip blade material 5 for bending it in a CW or CCWdirection, respectively.

The automatic bending machine for automatically bending a strip bladematerial of the present invention may be configured such that an upperbelt wheel 2 is provided in a lower machine cabinet 101 extending from amachine cabinet 1 in concentricity with the nozzle column 32 or thereinforcing rod 1021 independently of the nozzle column 32 or thereinforcing rod 1021.

Further, the automatic bending machine for automatically bending a stripblade material of the present invention may be configured such that thenozzle column 32 is connected to an upper reinforcing tube 321 providedin an upper machine cabinet 102 extending from a machine cabinet 1 forreinforcement, in order to allow the nozzle 3 to withstand the strikingimpact applied by the CW-direction bending tool 4 or the CCW-directionbending tool 40.

In addition, the automatic bending machine for automatically bending astrip blade material of the present invention may be configured suchthat a magnet 221 or a ball plunger 222 is provided for a protrusion 22or a groove stopper 44, or a spring 223 is provided for a bending toolsupport 42, in order to rapidly return the CW bending tool 4 or the CCWbending tool 40 from the working position to the retract one.

Further, the automatic bending machine for automatically bending a stripblade material of the present invention may be configured such that thenozzle column 32 is connected to a reinforcing tube 321 provided in theupper machine cabinet 102 extending from the machine cabinet 1 by meansof a screw. By providing such a configuration, removing the reinforcingtubes 321 will allow the nozzle 3, the CW-direction bending tools 4, theCCW-direction bending tools 40, and the like to be pulled forward fromthe machine cabinet 1 together with the nozzle supports 11, facilitatingthe tooling replacement.

The cutting mechanism is formed in the scissors-like shape as shown inFIG. 11-A-1, and is capable of cutting a strip blade material 5 as highas 23.8 mm at once.

In addition, the setup method of the present invention will allow aworkpiece having an enclosed rectangular geometry as shown in FIG. 13-Ato be cut without “two-leaf cutting” being caused.

The present invention has the following effects.

Because, with the present invention, two different bending tools areprovided as described above, bending by an angle of over 90 degrees canbe performed.

Because, with the present invention, two different bending tools areprovided as described above, there is no need for the bending tool beingvertically moved to the opposite side, thus tool jamming will not occur.

Because, with the present invention, two different bending tools areprovided as described above, there is no need for the bending tool beingvertically moved to the opposite side, thus the working time can besaved. In addition, the CW-direction bending tool 4 or the CCW-directionbending tool 40 turned for striking can be retracted with the magnet 221or the spring 223 for the subsequent bending.

Because, with the present invention, two different bending tools areprovided as an integral part, as described above, the rigidity of theCW-direction bending tool 4 and the CCW-direction bending tool 40 can bemaintained, which assures bending with high accuracy. The “integralpart” means that the tool is fixed with screws, or the like, rather thanbeing temporality inserted.

Because, with the present invention, no extra motor and cylinder arerequired as described above, the control system can be manufactured at alower cost. In addition, the problems which would be caused by the extramotor and cylinder can be eliminated.

Because, with the present invention, the nozzle column 32 may beconnected with the reinforcing tube 321 in the upper machine cabinet 102as described above, the nozzle 3 can be adapted to withstand thestriking impact applied by the CW-direction bending tool 4 or theCCW-direction bending tool 40.

With the present invention, the nozzle column 32 may be connected to areinforcing tube 321 provided in the upper machine cabinet 102 extendingfrom the machine cabinet 1 by means of a screw, as described above, thusby providing such a configuration, removing the reinforcing tubes 321will allow the nozzle 3, the CW-direction bending tools 4, theCCW-direction bending tools 40, and the like to be pulled forward fromthe machine cabinet 1 together with the nozzle supports 11, facilitatingthe tooling replacement. For example, the tooling for blades of 2 P witha thickness of 0.72 mm can be easily replaced with that for blades of 3P with a thickness of 1.08 mm.

In addition, the cutting tool of the present invention is capable ofcutting a strip blade material 5 as high as 23.8 mm at once.

In addition, the setup method of the present invention will allow aworkpiece having an enclosed rectangular geometry as shown in FIG. 13-Ato be cut without “two-leaf cutting” being caused.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a first embodiment of theautomatic bending machine of the present invention;

FIG. 2 is a perspective view illustrating a first embodiment of thebending tool of the present invention;

FIG. 3 is a perspective view illustrating a combination of the nozzleand bending tool of the present invention;

FIG. 4-A, FIG. 4-B, and FIG. 4-C are plan views illustrating anembodiment of the process of bending a strip blade material of thepresent invention;

FIG. 5-A is a perspective view illustrating a second embodiment of theautomatic bending machine of the present invention;

FIG. 5-B is a sectional plan view illustrating the configuration of theguide groove and guide protrusion in the above-mentioned secondembodiment;

FIG. 6-A, FIG. 6-B, and FIG. 6-C are perspective views illustratingsecond, third, and fourth types of bending tool puller-back element usedwith the present invention, respectively;

FIG. 7-A is a perspective view illustrating a second embodiment of thebending tool of the present invention;

FIG. 7-B is a perspective view illustrating a third embodiment of thebending tool of the present invention;

FIG. 8-A is a sectional side view of a third embodiment of the automaticbending machine of the present invention (drawing of the lower halfsection of the apparatus being omitted);

FIG. 8-B is a partially enlarged sectional side view of a modificationof the above-mentioned third embodiment of the automatic bending machineof the present invention;

FIG. 9-A and FIG. 9-B are plan views of bending tools of the prior art;

FIG. 10-A is a front view of a cutting tool of the prior art;

FIG. 10-B is a perspective view of another cutting tool of the priorart;

FIG. 10-C is a front view of the same cutting tool as FIG. 10-B;

FIG. 11-A is a front view of an embodiment of the cutting unit of thepresent invention, the cutting tool components being in one position,respectively;

FIG. 11-B is a side view of the cutting unit;

FIG. 11-C is a front view of the cutting unit, the cutting toolcomponents being in the other position, respectively;

FIG. 12-A-1 is a front view of an embodiment of the cutting tool of thepresent invention, the components thereof being in one position,respectively;

FIG. 12-A-2 is a sectional plan view of the cutting tool, the componentsthereof being in one position, respectively, and the workpiece beforebeing cut;

FIG. 12-A-3 is a sectional front view of the cutting tool, thecomponents thereof being in one position, respectively, and theworkpiece before being cut;

FIG. 12-B-1 is a front view of the cutting tool, the components thereofbeing in the other position, respectively;

FIG. 12-B-2 is a sectional plan view of the cutting tool, the componentsthereof being in the other position, respectively, and the workpieceafter being cut;

FIG. 12-B-3 is a sectional front view of the workpiece after being cut;

FIG. 13-A is a sectional plan view of a workpiece having an enclosedrectangular geometry.

FIG. 13-B is a sectional plan view illustrating how the above-mentionedworkpiece is cut with the cutting tool of the present invention;

FIG. 13-C illustrates a first step comprised in the method of thepresent invention for preventing the occurrence of “two-leaf cutting”with an enclosed rectangular geometry of workpiece;

FIG. 13-D illustrates a second step in the method of the presentinvention for preventing the occurrence of “two-leaf cutting” with anenclosed rectangular geometry of workpiece;

FIG. 13-E illustrates a third step in the method of the presentinvention for preventing the occurrence of “two-leaf cutting” with anenclosed rectangular geometry of workpiece; and

FIG. 14 is a side view illustrating an embodiment of the automaticbending machine including the both-end cutting apparatus of the presentinvention in which a miter cutting unit and a straight cutting unit areadditionally provided ahead of the bending apparatus.

DETAILED DESCRIPTION OF THE INVENTION

Hereinbelow, exemplary embodiments of the present invention will bedescribed with reference to the attached drawings.

FIG. 1 is a perspective view illustrating a first embodiment of theautomatic bending machine for manufacturing of steel rule cutting diesof the present invention. A nozzle 3 for guiding a strip blade material5 which is intermittently fed has nozzle supports 11 at the top andbottom thereof that are inserted into a machine cabinet 1. At the tip ofthe nozzle 3, a nozzle gate 31 from which the strip blade material 5juts out is provided. At the top and bottom of the nozzle 3, a nozzlecolumn 32 which penetrates through a concentric hole 41 in aCW-direction bending tool 4, and the same in a CCW-direction bendingtool 40 is provided. In FIG. 3, the relationship among the nozzle 3, theCW-direction bending tool 4, and the CCW-direction bending tool 40 isillustrated in detail. In addition, FIG. 2 shows the CW-directionbending tool 4 and the CCW-direction bending tool 40 in detail. TheCW-direction bending tool 4 or the CCW-direction bending tool 40 isturned around the nozzle gate 31 to strike the side of the strip bladematerial 5 to bend it. In the present invention, two different bendingtools which are turned in a clockwise or counterclockwise direction whenviewed from the top, for working (in other words), the CW-directionbending tool 4 and the CCW-direction bending tool 40, are provided. Ascan be seen from FIG. 2, these two tools have the same geometry like avertical trough, a bending tool support 42 extending at right angles atthe top and bottom thereof. In the bending tool support 42, a concentrichole 41 through which the nozzle column 32 penetrates is provided. TheCW-direction bending tool 4 and CCW-direction bending tool 40 aresuperposed one upon the other, and as shown in FIG. 3, are penetrated bythe nozzle column 32 to be fixed to the nozzle 3. When viewed from thefront, the CCW-direction bending tool 40 at the left side is superposedon the CW-direction bending tool 4 at the right side. To assemble insuch a configuration, the nozzle column 32 is inserted into theCW-direction bending tool 4 and the CCW-direction bending tool 40 placedon a column base 33, and then fixed with a screw to the column base 33on the top and bottom of the nozzle 3, respectively. The nozzle 3 isinserted into the machine cabinet 1 by means of the integrated nozzlesupports 11 at the top and bottom of the nozzle 3. The nozzle column 32is further inserted into the upper belt wheel 2 or the lower belt wheel21 which is turned by the timing belt 25. The timing belt 25 connectsbetween the upper and lower synchronous belt wheel 27 and the upper beltwheel 2 or the lower belt wheel 21. The upper and lower synchronous beltwheel 27 is connected to the synchronous lower belt wheel 24 and theupper and lower synchronous belt wheel 27 by the synchronous shaft 26.The upper and lower synchronous belt wheel 27 is connected to a turningmotor (not shown) by the timing belt 25. When the turning motor is run,the force is transmitted to the upper and lower synchronous belt wheel27 to turn the upper belt wheel 2 and the lower belt wheel 21. On theback of the upper belt wheel 2 and the lower belt wheel 21, a protrusion22 is provided, and when the motor is run, the protrusion 22 strikes thebending tool support 42.

FIG. 4-A, FIG. 4-B, and FIG. 4-C illustrate the process of bending thestrip blade material 5 by the tool of the present invention. FIG. 4-Ashows the initial state, the CW-direction bending tool 4 and theCCW-direction bending tool 40 being in the home position. When theprotrusion 22 is turned counter clockwise (CCW), the CCW-directionbending tool 40 is struck against the strip blade material 5 as shown inFIG. 4-B. When the protrusion 22 is further turned CCW, theCCW-direction bending tool 40 and the nozzle gate 31 bend the stripblade material 5 by an angle of over 90 degrees as shown in FIG. 4-C. Asa result of such a configuration, the strip blade material 5 can be bentto an angle close to 130 degrees, as compared to 90 degrees with aconstruction as shown in FIG. 9-A.

FIG. 5-A shows a second embodiment of the automatic bending machine ofthe present invention. In this embodiment, a guide protrusion 43 isprovided for each of the CW-direction bending tool 4 and theCCW-direction bending tool 40 in place of the protrusion 22 in theabove-described embodiment, while the upper belt wheel 2 and the lowerbelt wheel 21 are provided with a guide groove 23. At both ends of theguide groove 23, a groove stopper 44 which butts against the guideprotrusion 43 is provided. Thereby, the same effect as that which can beobtained by the above-described embodiment is given. However, even ifthe guide groove 23 is not provided, the CW-direction bending tool 4 andthe CCW-direction bending tool 40 can be turned, thus providing a guidegroove is not a requisite for the present embodiment, and instead of thegroove stopper 44, a protrusion 22 may be provided.

FIG. 8-A is a sectional side view of a third embodiment of the automaticbending machine of the present invention (drawing and description of thelower half section of the apparatus being omitted). With the presentembodiment, the nozzle column 32 on the nozzle 3 is free from the loadimposed by the timing belt in driving. Specifically, in order to makethe nozzle column 32 free from the transmission of the force through theupper belt wheel 2 and the protrusion 22, the belt wheel 2 and theprotrusion 22 are provided in the lower machine cabinet 101 extendingfrom the machine cabinet 1. The belt wheel 2 includes a hollow beltwheel 210 which is disposed concentrically with the nozzle column 32,and a tubular connecting element 212, being turned by the timing belt.The lower portion of the belt wheel 2 includes a portion which turnswith a needle bearing 211, and the bottom part on which the protrusion22 is mounted. Thereby, the nozzle column 32 is free from the loadimposed by the timing belt drive.

In addition, the nozzle column 32 on the top of the nozzle 3 may bereinforced because it is subjected to the bending pressure by theCW-direction bending tool 4 or the CCW-direction bending tool 40. To dothis, a reinforcing tube 321 penetrating through the upper machinecabinet 102 extending from the machine cabinet 1 is providedconcentrically with the nozzle column 32, and the nozzle column 32 isfixed thereto by means of a screw at the end. Thereby, the back of thenozzle 3 is inserted into the machine cabinet 1, and the top and bottomthereof are fixed to the reinforcing tube 321 in the present embodiment,which allows the nozzle 3 to withstand the striking impact applied bythe CW-direction bending tool 4 or the CCW-direction bending tool 40. InFIG. 8-A, the CW-direction bending tool 4 is omitted from being shownfor ease of understanding.

With the protrusion 22 as shown in FIG. 4-A, FIG. 4-B, and FIG. 4-C, astrong magnet 221 is embedded in the area where the protrusion 22 isstruck against the bending tool support 42. The purpose of imbedding ofthe magnet 221 is this: When the strip blade material 5 is to be bent toform a desired circular arc, it is first fed by 1 mm, and struck once bythe CW-direction bending tool 4 or the CCW-direction bending tool 40,then the CW-direction bending tool 4 or the CCW-direction bending tool40 is once reversely turned to the retract position before the stripblade material 5 is fed by another 1 mm. Then, the strip blade material5 is fed by another 1 mm, and is struck the second time by CW-directionbending tool 4 or the CCW-direction bending tool 40. A desired circulararc is thus formed by repeating this cycle, and this arc forming methodis called the polyline method. This method involves reverse turning theCW-direction bending tool 4 or the CCW-direction bending tool 40 to theretract position. Therefore, a magnet is used, and as the magnet, aneodymium one is optimum. In the position as shown in FIG. 4-A, theCW-direction bending tool 4 and the CCW-direction bending tool 40 areattracted to the protrusion 22. In the position as shown in FIG. 4-B,the CW-direction bending tool 4 is butted against the side wall of thenozzle 3, being left there, and the CCW-direction bending tool 40 isfurther turned to bend the strip blade material 5 as shown in FIG. 4-C,then the protrusion 22 being reversely turned to the retract position.Even during that reverse turning, the CCW-direction bending tool 40 canbe returned to the retract position, being attracted and held by themagnet 221. This description of the bending operation is also applicablewhen the CW-direction bending tool 4 is used for carrying out aCW-direction bending.

In the present invention, the puller-back element for the CW-directionbending tool 4 and the CCW-direction bending tool 40 is not particularlylimited to a magnet, and any type thereof may be adopted, provided thatthe puller-back element can return the CW-direction bending tool 4 orthe CCW-direction bending tool 40 to the retract position when theprotrusion 22 is reversely turned. Examples of other types ofpuller-back element are shown in FIG. 6-A, FIG. 6-B, and FIG. 6-C. InFIG. 6-A, a ball plunger 222 is embedded in the protrusion 22 instead ofthe above-mentioned magnet. In FIG. 6-B, one end of the spring 223 isconnected to the bending tool support 42, and the other end is to thenozzle support 11. In this case, in bending, the torque for theCW-direction bending tool 4 or the CCW-direction bending tool 40overcomes the force of the spring 223, while, in reverse turning, theCW-direction bending tool 4 or the CCW-direction bending tool 40 ispulled back by the force of the spring 223 extended. In FIG. 6-C, bothsprings 223 are connected to the nozzle support 11. The effect of theseother types of puller-back element is equivalent to that of the magnet221.

With the embodiment as shown in FIG. 8-A (drawing and description of thelower half section of the apparatus being omitted), replacement of thetooling can be performed with ease. Generally, automatic bendingmachines bend the blade of 1.5 P with a thickness of 0.5 mm, 2 P with athickness of 0.72 mm, 3 P with a thickness of 1.08 mm, or 4 P with athickness of 1.44 mm. Thus, when the strip blade material 5 having adifferent thickness is to be bent, the nozzle 3, the CW-directionbending tool 4, and the CCW-direction bending tool 40 must be replacedwith those for the different thickness. However, with the embodiment asshown in FIG. 1, the replacement operation takes so much time as wouldrender it impracticable. On the contrary, with the embodiment as shownin FIG. 8-A, it is only required that the handwheel 322 for thereinforcing tube 321 be turned to disengage the screw at the bottom ofthe reinforcing tube 321 from the nozzle column 32; the nozzle 3, theCW-direction bending tool 4, and the CW-direction bending tool 40 bepulled forward to be removed; the desired tooling be inserted; and thereinforcing tube 321 be again fixed to the nozzle column 32 (descriptionof the lower half section of the apparatus being omitted).

In the present invention, the CW-direction bending tool 4 and theCCW-direction bending tool 40 are not limited to those as shown in FIG.2, and for example, those as shown in FIG. 7-A may be used. TheCW-direction bending tool 4 and the CCW-direction bending tool 40 asshown in FIG. 7-A each consist of three components which are assembledusing screws 45, thus rendering the manufacture easier. In this case,the need for the column base 33 as shown in FIG. 3 is eliminated, andthe nozzle column 32 can be directly mounted into the nozzle 3. Then,after the bending tool support 42 being fitted to the nozzle column 32,the CW-direction bending tool 4 and the CCW-direction bending tool 40are finally fixed using the screws 45, respectively. The CCW-directionbending tool 40 and the CW-direction bending tool 4 as shown in FIG. 7-Aare mutually different in geometry, the CCW-direction bending tool 40being accommodated in the inside of the CW-direction bending tool 4.Thus, the CW-direction bending tool 4 and the CCW-direction bending tool40 need not always have the same geometry. FIG. 7-B shows a CW-directionbending tool 4 having another geometry. With this configuration, whenthe CW-direction bending tool 4 is worn, only the CW-direction bendingtool 4 need be replaced with new one, with the bending tool support 42being left mounted. This description is also applicable to theCCW-direction bending tool 40.

FIG. 8-B is a partially enlarged sectional side view of a modificationof the embodiment as shown in FIG. 8-A. In this modification, areinforcing rod 1021 is used in place of the reinforcing tube 321 inFIG. 8-A. The reinforcing rod 1021 is threaded at the end, and is fixedto an insertion hole 3211 which is provided in the top of the nozzle 3.In this case, there is no need for the nozzle column 32, and the end ofthe reinforcing rod 1021 penetrates through the concentric hole 41 inthe respective bending tools to be fixed to the insertion hole 3211 bymeans of the screw.

In the embodiment as shown in FIG. 8-A (drawing of the lower halfsection of the apparatus being omitted), the respective protrusions 22strike the respective bending tool supports 42, being synchronizedthrough the upper belt wheel 2 and the lower belt wheel 21, however,both upper and lower belt wheels are not always required. Only either ofthem may be provided. However, providing both upper and lower beltwheels eliminates the uneven distribution of the force on the stripblade material 5, which allows the size of the CW-direction bending tool4 and the CCW-direction bending tool 40 to be reduced.

FIG. 14 shows an embodiment of the automatic bending machine includingthe both-end cutting apparatus of the present invention in which a mitercutting unit 60 and a straight cutting unit 601 are additionallyprovided ahead of the bending apparatus. As shown in FIG. 11-A, FIG.11-B, and FIG. 11-C, the cutting tool 6 is made up of a set of threescissors-like cutting tool components. More specifically, the cuttingtool 6 consists of two higher-profile cutting tool components 650 onboth sides, a lower-profile cutting tool component 651 in the middle,and a through pin 652 which penetrates through these three cutting toolcomponents. The three cutting tool components are connected tomini-cylinders 654 through a bar 653 at the top thereof, respectively.The miter cutting unit 60 is vertically moved by an elevating motor 655.When the strip blade material 5 is to be cut, the miter cutting unit 60is lowered by the elevating motor 655 to the position where the stripblade material 5 can be cut, being pinched by the above-mentioned threecutting tool components. Then, the mini-cylinders 654 are operated, thestate as shown in FIG. 11-A being changed into that as shown in FIG.11-C, the strip blade material 5 being cut.

FIG. 12-A-1, FIG. 12-A-2, FIG. 12-A-3, FIG. 12-B-1, FIG. 12-B-2, andFIG. 12-B-3 illustrate how the strip blade material 5 is cut by themiter cutting unit 60. In this case, the three cutting tool componentsare provided with different die geometries (in other words), a workpiecefront end miter cutting edge 63 and a workpiece rear end miter cuttingedge 631 as shown in FIG. 12-A-1, FIG. 12-A-2, FIG. 12-A-3.

The respective higher-profile cutting tool components 650 andlower-profile cutting tool component 651 for miter geometry cutting havea cutting edge on both sides. Therefore, the strip blade material 5 canbe pinched with the higher-profile cutting tool components 650 and thelower-profile cutting tool component 651 being positioned as shown inFIG. 12-B-1 and 12-B-2. Then, the positions of the higher-profilecutting tool components 650 and the lower-profile cutting tool component651 can be changed into those as shown in FIG. 12-A-1 and FIG. 12-A-2 tocut the strip blade material 5. In other words, cutting can be carriedout regardless of whether the higher-profile cutting tool components 650and the lower-profile cutting tool component 651 are positioned as shownin FIG. 12-A-1 and FIG. 12-A-2, or in FIG. 12-B-1 and 12-B-2.

Especially when the strip blade material has a geometry of an enclosedrectangle as shown in FIG. 13-A, the conventional cutting tool as shownin FIG. 10-B causes tool jamming, thus the bending steps may have to bereversed. Further, depending upon the geometry of the strip bladematerial, occurrence of tool jamming cannot be avoided, even if thebending steps are reversed. With the present invention, such a problemwill not be caused.

For a rectangular geometry as shown in FIG. 13-B, if the cutting tool 6is lowered such that the higher-profile cutting tool components 650 andthe lower-profile cutting tool component 651 are positioned as shown inFIG. 12-B-1 and FIG. 12-B-2, tool jamming will not be caused, becausethe two higher-profile cutting tool components 650 are not positioned onthe rectangular geometry side. However, the one cutting tool component651 must be inserted between the overlapped portions of the strip bladematerial 5. Selection of the positions of the higher-profile cuttingtool components 650 and the lower-profile cutting tool component 651 asshown in either FIG. 12-A-1 and FIG. 12-A-2, or FIG. 12-B-1 and FIG.12-B-2, depending upon the geometry of the strip blade material 5, willprevent tool jamming.

FIG. 13-C, 13-D, and 13-E illustrate the respective steps included inthe setup method of the present invention for preventing the occurrenceof “two-leaf cutting” in the end cutting of a workpiece having anenclosed rectangular geometry. Even if the higher-profile cutting toolcomponents 650 and the lower-profile cutting tool component 651 arepositioned as shown in FIG. 13-B, but when the cutting tool tip 65lowered is not inserted between the overlapped portions of the stripblade material 5, the “two-leaf cutting” will be caused. Thus, beforethe cutting tool tip 65 is lowered, a spacing must generally be providedbetween the overlapped portions by using fingers so as to allow thecutting tool tip 65 of the cutting tool component 651 to be insertedbetween the overlapped portions. Then, to eliminate this difficulty,after the three cutting tool components being positioned such that thetwo higher-profile cutting tool components 650 are positioned on theside opposite to the rectangular geometry side, the strip blade material5 is once advanced to a position where “two-leaf cutting” will notoccur, as shown in FIG. 13-C, and then the cutting tool 6 is lowered.The cutting tool tip 65 of the cutting tool component 651 is lowered toa level of the same as or under that of the top edge of the strip bladematerial 5. Then the strip blade material 5 is retracted (FIG. 13-D).Finally, the strip blade material 5 is retracted by the same amount asthat of the advance from the desired position (FIG. 13-E). This setupmethod of the present invention is applicable to the conventionalcutting tool as shown in FIG. 10-B.

Thus, there is no longer the need for using fingers to give a spacingbetween the overlapped portions of the workpiece.

DESCRIPTION OF REFERENCE NUMERALS

-   1: Machine cabinet-   101: Lower machine cabinet-   102: Upper machine cabinet-   1021: Reinforcing rod-   11: Nozzle support-   2: Upper belt wheel-   21: Lower belt wheel-   210: Hollow belt wheel-   211: Needle bearing-   212: Tubular connecting element-   22: Protrusion-   221: Magnet-   222: Ball plunger-   223: Spring-   23: Guide groove-   24: Synchronous lower belt wheel-   25: Timing belt-   26: Synchronous shaft-   27: Upper and lower synchronous belt wheel-   3: Nozzle-   31: Nozzle gate-   32: Nozzle column-   321: Reinforcing tube-   3211: Insertion hole-   322: Handwheel-   33: Column base-   4: CW-direction bending tool-   40: CCW-direction bending tool-   41: Concentric hole-   42: Bending tool support-   43: Guide protrusion-   45: Screw-   44: Groove stopper-   5: Strip blade material-   6: Scissors-like movable tool (cutting tool)-   61: Stationary blade-   60: Miter cutting unit-   601: Straight cutting unit-   650: Higher-profile cutting tool-   651: Lower-profile cutting tool-   652: Through pin-   653: Bar-   654: Mini-cylinder-   655: Elevating motor-   63: Workpiece front end miter cutting edge-   631: Workpiece rear end miter cutting edge-   65: Cutting tool tip-   7: Bridge die-   71: Feed rollers

1. An apparatus for cutting both ends of a strip blade material,comprising a miter cutting unit and a straight cutting unit providedtogether with an automatic bending machine, wherein a cutting toolconsists of two higher-profile cutting tool components on both sides, alower-profile cutting tool component in the middle, and a through pinpenetrating through these three; the three cutting tool components areconnected to mini-cylinders through a bar at the top thereof,respectively; the miter cutting unit is vertically moved by an elevatingmotor; when the strip blade material is to be cut, the miter cuttingunit is lowered by the elevating motor to the position where the stripblade material can be cut, being pinched by the above-mentioned threecutting tool components; then, the mini-cylinders are operated, thepositions of the three cutting tool components being changed to cut thestrip blade material; and the three cutting tool components are providedwith different die geometries, i.e., a workpiece front end miter cuttingedge and a workpiece rear end miter cutting edge.
 2. A setup method forpreventing a “two-leaf cutting” by only operating the machine withoutusing fingers in cutting the end of a strip blade material having anenclosed rectangular geometry using the apparatus as defined in claim 1,comprising the steps of: after the three cutting tool components beingpositioned such that the two higher-profile cutting tool components arepositioned on the side opposite to the rectangular geometry side, thestrip blade material being once advanced to a position where “two-leafcutting” will not occur; then the cutting tool being lowered; thecutting tool tip of the cutting tool component being lowered to a levelof the same as or under that of the top edge of the strip bladematerial; then the strip blade material being retracted; and finally,the strip blade material being retracted by the same amount as that ofthe advance from the desired position.